Heart disease is the leading cause of death globally, killing 17.3 million people worldwide. It is also the leading cause of death among men and women in the United States accounting for more than half of the deaths reported in the US in 2009. Estimates from the CDC, suggest that heart failure alone costs the country $34.4 billion annually in medication, health care, and loss in productivity.
Heart failure occurs when a loss of cardiac muscle tissue impairs heart function leading to an inability to sufficiently pump oxygenated blood to other parts of the body. Cardiac tissue can be damaged by myocardial infarction or a heart attack, when the blood supply to the heart is lost resulting in the damage or death of impacted tissue. Unfortunately, these conditions cannot be reversed. However, cardiac regenerative medicine offers promising therapies that can improve heart function and health.
Human pluripotent stems cells can now be differentiated into cardiomyocytes, which can be transplanted or grafted into patients following cardiac damage. Recent reports have demonstrated certain methods for the inducing the differentiation of human induced pluripotent stem cells and human embryonic stem cells into cardiomyocytes. Another method that has garnered attention recently is induced pluripotent stem cell (iPSC) technology. iPSC technology differentiates a pluripotent stem cell from a non-pluripotent stem cell, by inducing the expression of certain genes.
Protocols for cardiomyocyte differentiation generally yield a heterogeneous assortment of cardiomyocytes, undifferentiated cells and non-cardiomyocytes. Obtaining enriching or purifying cardiomyocyte preparations still remains challenging, diminishing the clinical utility of this technology. While the existing methods provide a level of cardiomyocyte purity suitable for research purposes, none of these are suitable for clinical applications. It is known that transplanting a mixed population of cardiovascular cells into patients can lead to an adverse outcome such as teratoma formation or other abnormal growths.
Tyagi et al. report molecular beacons as probes that fluoresce upon hybridization. See Nature Biotechnology, 1996, 14(3):303-8.
Braam et al. report cardiomyocytes from human pluripotent stem cells in regenerative medicine and drug discovery. See Trends in Pharmacological Science, 2009, 30, 536-545.
Seligman et al. reports a method for isolating pluripotent/multipotent stem cells from blood by using the pluripotent and germ-line DAZL gene as a marker. Stem Cells and Development, 2009, 18(9): 1263-1271. See also U.S. Pat. No. 6,692,965
King et al. report high-throughput tracking of pluripotent human embryonic stem cells with dual fluorescence resonance energy transfer molecular beacons. See Stem Cells Dev, 2011, 20(3): 475-484.
Larsson et al. report sorting live stem cells based on Sox2 mRNA expression. See PLoS ONE, 2012, 7(11): e49874.
Elliott et al reports NKX2-5eGFP/w hESCs for isolation of human cardiac progenitors and cardiomyocytes. See Nature Methods, 2011, 8 1037-1040.
Uosaki et al. report purification of cardiomyocytes from human embryonic and induced pluripotent stem cells by VCAM1 surface expression. See PLoS ONE, 2011, 6:e23657. Dubois et al. report SIRPA is a specific cell-surface marker for isolating cardiomyocytes derived from human pluripotent stem cells. See Nature Biotechnology, 2011, 29:1011-1018.
Yang et al. report human cardiovascular progenitor cells develop from a KDR+ embryonic-stem-cell-derived population. See Nature, 2008, 453:524-528.
Kattman et al. report stage-specific optimization of activin/nodal and bmp signaling promotes cardiac differentiation of mouse and human pluripotent stem cell lines. See Cell Stem Cell, 2011, 8:228-240.
Bu et al. report human ISL1 heart progenitors generate diverse multipotent cardiovascular cell lineages. See Nature, 2009, 460:113-117.
Huber et al. report identification and selection of cardiomyocytes during human embryonic stem cell differentiation. See Faseb Journal, 2007, 21:2551-2563.
Zwi et al. report cardiomyocyte differentiation of human induced pluripotent stem cells. Circulation, 2009, 120:1513-1523.
Shiba et al. report human es-cell-derived cardiomyocytes electrically couple and suppress arrhythmias in injured hearts. Nature, 2012, 489(7415):322-5
U.S. Pat. No. 8,039,259 reports buffering solutions for electroporation.
References cited herein are not an admission of prior art.